<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>border-color效果</title>
  <style type="text/css">
    body {
      color: #fff;
      background: #222;
    }

    h1 {
      font-size: 14px;
      font-family: "Microsoft Yahei";
      text-align: center;
    }

    .spinner {
      width: 10em;
      height: 10em;
      border-radius: 100%;
      margin: 100px auto;
      border: 1.1em solid rgba(255, 255, 255, .2);
      border-left-color: #fff;
      animation: loop .7s linear infinite;
    }

    @keyframes loop {
      from {
        transform: rotate(0deg);
      }

      to {
        transform: rotate(360deg);
      }

    }
  </style>
</head>
<body>
<h1>请使用webkit内核标准浏览器查看效果</h1>
<div class="spinner"></div>
</body>
</html>
